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The Vanara feat Climbing Tail is as follows:

Your tail makes it much easier for you to climb. You gain a +2 circumstance bonus to Athletics checks to Climb, you gain the Combat Climber skill feat, and you reduce the number of free hands required to Climb or Trip by one.

And Combat Climber is as follows:

Your techniques allow you to fight as you climb. You’re not flat-footed while Climbing and can Climb with a hand occupied. You must still use another hand and both legs to Climb.

Your techniques allow you to fight as you climb. You’re not offguard while Climbing and can Climb with a hand occupied. You must still use another hand and both legs to Climb.

(Both are identical, pick your favourite.)

As written:
• Climbing normally requires two free hands.
• If you have Combat Climber, you can also climb by using one hand and two legs.
• If you have Climbing Tail, you gain Combat Climber, and also reduce the number of free hands needed by one. (You presumably also have to use your tail, but for some reason this isn't listed as a mechanical requirement. Perhaps it's merely being used to balance and steer, like many actual monkeys do.)

So... how exactly do these things interact, since there's a bit of ambiguity here? As written, which of these climbing options are valid?
1. You can climb using two free hands and no other limbs. [Default, should still be available.]
2. You can climb using one free hand and no other limbs. [Default, reduced by Climbing Tail.]
3. You can climb using one free hand and two legs. [Combat Climber, should still be available.]
4. You can climb using zero free hands and two legs. [Combat Climber, reduced by Climbing Tail.]

I would assume that all but #2 is allowed, myself, though I'm not entirely sure. I've also heard people (including at least one person that's reasonably familiar with the game) claim that Climbing Tail's hand requirement reduction gets folded into Combat Climber because they "do the same thing" (which appears to be untrue, since one is an alternate method and one is a requirement reduction), and there doesn't seem to be a real consensus over how exactly Climbing Tail works, so I figured I'd ask here. Which of these are correct, and are there any I missed?

Generally, the number of components a spell has is the same as its action cost: 1-action spells have one component, 2-action ones have two components, and 3-action ones have three components. Is this an actual design requirement, that all spells must have one component for each action casting takes? Or is it just a general design choice that can be ignored if appropriate when designing new spells?

[Wasn't sure whether this belongs here, or in the 3rd-party/homebrew rules & design section. Feel free to move it if it's in the wrong place.]